Researchers Defend Finding of Symptom-Free Coronavirus Spread

(Bloomberg) --

Researchers stood behind their finding that a woman wasn’t feeling ill at the time she set off a cluster of coronavirus cases in Germany last month, adding fuel to a debate over how the disease spreads.

Their response on Friday counters a statement from German health officials earlier this week that the Chinese woman was in fact experiencing symptoms. The authorities from the Robert Koch Institute, a government biomedical agency, and the Bavarian health ministry interviewed the woman after she flew back to China on Jan. 22.

Determining how often the disease is spread by people without symptoms -- which can alert patients and others to the presence of disease -- may be key to efforts to slow the pathogen’s advance. The death toll in China has climbed to more than 600, with the number of cases rising to more than 31,000 since the illness was first reported in Wuhan, China, in late December.

The government institute in Berlin declined to comment beyond its earlier statement. The organization had said that the woman described having symptoms including back pain while in Germany and said she took anti-fever medication.

There have been other reports of asymptomatic transmission of the coronavirus in China. However, even if there are rare instances, it’s unlikely to become a major factor in the spread of the virus, Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in the U.S., told reporters on Jan. 28.

Airport Screening

Airport screening of passengers depends on symptoms like fever to detect people potentially infected with the coronavirus, also called 2019-nCoV. The researchers’ paper published late last month in the New England Journal of Medicine indicated that the woman transmitted the virus while still in the pre-symptomatic phase.

The researchers said they published that paper quickly because of the importance of the issue, and afterwards were able to speak with the patient herself in China. According to an addendum they sent to the journal, the woman said that after attending meetings on Jan. 20 in Germany, she woke up at midnight feeling slightly warm, but not feverish, and took an over-the-counter Chinese medicine typically used for pain and fever as a precautionary measure. She experienced fatigue and minor pain on Jan. 21., which she attributed to jet lag.

The next day she felt slightly cold before flying out of Munich that night. The first time she realized she was sick was the evening of Jan. 23 when she was back in China, they wrote.

Message Still Stands

Two researchers among the 17 authors of the original paper -- Michael Hoelscher and Camilla Rothe of the Medical Center of the University of Munich -- signed the letter to the journal.

“The message of our initial letter still stands,” they wrote. People across the medical world can “judge by themselves if the patient showed any relevant symptoms or not.”

Since the Chinese woman’s visit to the German headquarters of auto-parts supplier Webasto SE -- located a half hour south of Munich -- the company has experienced a rash of coronavirus cases. Eight of its German employees have tested positive for the disease as well as the wife and two children of one of those workers. Beyond that, two Webasto employees from China who visited the German campus last month -- including the woman recently interviewed by German health authorities -- have tested positive.

To contact the reporters on this story: James Paton in London at jpaton4@bloomberg.net;Tim Loh in Munich at tloh16@bloomberg.net

To contact the editors responsible for this story: Eric Pfanner at epfanner1@bloomberg.net, John Lauerman, Andrew Noël

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